System for controlling charging of storage batteries



S. K. LESSEY SYSTEM FOR CONTROLLING CHARGING OF STORAGE BATTERIES Sept. 25, 1945.

Filedxuarcih 24, 1944l Mme-ss:

Patented Sept. 25, 1945 SYSTEM FOR CON TROLLING CHARGING OF STORAGE BATTERIES Samuel K. Lessey, Chap The Electric Storage 8 Claims.

This invention relates to systems for ling the charging of storage batteries, and more particularly to systems in which a plurality of charging sources is provided.

An object of the invention is to provide, in a system including a storage battery and a plurality of charging sources, means for automatically and at predetermined time intervals connectng one of the charging sources to the battery, means for automatically connecting an additional charging source to the battery to provide for unusually heavy load conditions, and means responsive to battery voltage for disconnecting both charging sources from the battery.

A further object of the invention is to provide a charge control system whereby the results above cited may be accomplished by means of simple and comparatively inexpensive devices.

The invention comprises a storage battery and -its load circuit, at least two sources f charging current, means for periodically and at predetermined time intervals connecting one of the charging sources to the battery, other means responsive to'unusually heavy load conditions for connectment of the invention.

Referring to the diagram, I8 represents a storage battery connected to its load circuit II. Numerals I2 and I3 represent, respectively, a rst and second charging source, here shown as fullwave rectiers, of which I2 is connected to the A. C. circuit I4, I via conductors I6 and I1 respectively, and rectier I3 is connected to said A. C. circuit via conductors I8 and I 9. Interposed in conductor I1 are the contacts 2U of contactor 2| and in conductor I9 are the contacts 22 of contactor 23, whereby the rectiiers I2 and I3 may be connected to and disconnected from the A. C. circuit.

The D. C. terminals of rectifier I 2 are connected to the positive battery bus 24 via conductor 25, and to the negative bus 26 via conductor 21, and the D. C. terminals of rectier I3 are connected to the buses 24 and 26 via conductors 28 and 29, respectively.

The exciting coil 2Ia of contactor 2I is connected to the A. C. circuit I4, I5 via conductors paqua, N. Y., assignor to Battery Company, a corporation of New Jersey Application March 24, 1944, Serial No. 527,863

33 and l10n the one side and via conductor 3 I, contacts 32 of relay 33 and conductor 34. The exciting coil 33a of relay 33 is connected to the battery bus 26 via conductor 35 and to battery bus 24 via conductor 36, contacts 31 of battery voltage responsive relay 38 and conductor 39. The exciting coil 38a of relay 38 is connected on the one side to the battery bus 24 via conductor 40 and on the other side to battery bus 25 via conductor 4I, contacts of timer 42 and conductor 43.

Timer 42 comprises the synchronous motor 44 connected across the A. C. circuit I4, I5 via conductors 45 and 46, respectively. Through the worm gear 41 the synchronous motor drives the timing disk 48 of electrically conducting material on the other side is interrupted by the passage of the insulating insert 49 under brush 5I. The timer is so designed that this interruption of the circuit will occur at the desired frequency, Say once an hour or once every two hours, or at any other predetermined time interval suitable for the operating conditions to be met.

The mode of operation of that part of the apparatus above described is as follows:

When the circuit between conductors 4I and 43 timing disk 48, current will iiow through the exciting coil 38a of relay 38 from the battery positive bus 24, conductor 4D, coil 38a, conductor 4 brush 5I, disk 48, brush 58 and conductor 43 and bus 26 to the battery negative,y Ii the voltage of the battery is below that rapid rise of voltage at the contacts 31 will remain closed. This will permit current to ow from the battery bus 24 via conductor 39, contacts 31, conductor 36, coil 33a and conductor 35 tc bus 26. The contacts 32 of relay of contactor 2| from the A. C. circuit I4, I5 via conductors I1 and 3G, coil 2Ia, conductor 3|, contacts 32 and conductor 34. This will hold the contacts 20 of contactor 2| closed, thus keeping the rectier I2 connected to the A. C. circuit via conductors I6 and I1 and contacts 20, and the charging of the battery through rectifier I2 via conductors 25 and 21 will continue. A

the battery is not If, while the exciting circuit of relay 38 is closed through the timing disk 48, the voltage of the battery rises to a value corresponding to that of the steep part of the charging curve toward the end of charge, say about 2.4 volts per cell, the excitation of relay 38 will be suflicient to attract its armature and open the contacts 31. This will open the Vexciting circuit of relay 33, thus opening the contacts v-32 and interrupting the exciting circuit of contacter 2l, thereby opening the charging circuit at contacts 28. Relay 38 is fso designed that, after its excitation has increased to a value suicient to attract its armature and open its contacts 31, a much lower excitation, below that due to the reduced'batteryvoltage resulting from discharge, will be requiredto release its armature, so that the contacts 31, once opened, will remain open regardless ofrany normal drop in battery voltage, until the exciting circuit of coil 38a is opened at the timing disk,

As the timing disk 4,8 continues to rotate, the insulatinginsert 43 will be brought under the brush l, thus opening the exciting circuit of relay "3-8 and resetting this relay by allowing the contacts *.31 -to close. This will re-establish the ncl'ia'rging circuit by closing the contacts 32 of relay 33 -and therebyclosing "the contacts 20 of con- 'tactor'ZL l v Ater'the charging circuit has been opened by the operation of relay`38', as above described, if subjected to any appreciable amount of discharge before relay 38 is released and contacts 31are closed, thus re-establishing the charging circuit, the ensuing rise of battery voltage will quickly operate relay 38 and again open'the charging circuit. If,however, the load Vconditions Vare suchn that, after opening the chargin'g'circuit asa resultof the operation of relay 38, thefbattery is subjected to considerable discharge, a longerv time will elapse after charging is restored by the"rotatio`n of the timing disk before thebatte'ry voltage rises to a value which will operate relay 38 and again open the charging circuit. Obviously, instead of completely opening the charging circuit by contactor'Zl, the charging current may be reduced to a low value by any means well k'nowlntol those lskilled in the art Without'interferingwith the accomplishment of the results 'sought bytheapplicant.V For example, by closing nected'acros'sthe contacts`20, sothat whenthese contacts are opened the'charging current will be reduced vto'a small valuefbut not entirely interrrptd.. Theapparatus `in the art andS disclosed in'Patent 1,786,280 t0 Woodbridge. v

Undenunusually heavy load conditions, the value 'of Ycharging current delivered by charging source l2, after the charging circuit is re-established'bythe release of relay 38, may not exceed the loadon'the battery during that period by an amount suiiicient toV bring the battery voltage to aV value suicient to operate relay38 before the rotation Vof the tiiningdisk 48 again opens the exciting circuit "of relay 38; or the load may exceed the value of Vcharging current delivered by source I2, 'so that' the battery will receive no charge but willibeactually discharging. To avoid this result, there'is provided, according to this invention,`a second charging source i3 and additional apparatus' for automatically connecting said source'to"the"battery underA unusually heavy load Cndit0nS,`s follows:A Y

switch 16, the resistor 11 may be conthus far described is well known f .battery viabusZ,

"80a, conductors 82 and B3, contacts 54, conductor is connected across the battery l0 via bus 24, conductor 39, contacts 31, conductor 36, coil 52a, conductor 53 and bus 26. The contacts 54 of relay 52 are closed when this relay is excited. Relay 55 is provided with a coil 55a excited from the battery via bus 24, conductor 58, coil 55a, conductors 51 and 4l, timing disk 48, conductor 4-3and bus'28. Relayii is V.provided with contacts 58 whichare closed Whentthe relay is excited, and with contacts 59 which are opened when the relay is excited. Relay 88 is provided y with an exciting coil 60a connected across the conductor 6l, contacts 58, coil 56l and bus 24. lRelay 80 is provided with contacts ".54 and lili, both of which are closed when the relay is excited. The exciting coil a may also receive currentV from the battery via bus 24, conductor V58, contacts"54,`conductors 63 and 62, coil 88a,

contacts t4, conductor 66, and bus 26. Thus, so long as contactsl54 remain closed,theexcitation of relay 80, after being established by the closing of contacts 58, will be maintained'through-contacts 64`aiter contacts-have opened,l

Relay 61 isprovided with an exciting-coil {61a supplied with current 4from the battery viabus 24,'conductor`56, contacts 5,4, conductors-63land 12', contacts@` and 85, conductor 68, coil 51a, conductor -iil4 and bus 26. Relay 61 .is provided with contacts 18 and`1l, both of which are closed when the relayis excited. The excitation ofzrelay 51' willbe maintained after its Vcont-acts are once closed, via bus 12714,l conductor l58, contacts 54,.cvon ductors 83 and 13, contacts v1l), coil 61a, conductor 69- and bus`28.

A The 'exciting coil 23a of contacter V2 3 is provided with current fronti-,he A. C. circuit I4, l5y via conductor 14, contacts-1 Liconductor 15,-c0i1 23a, and

`conductor i9.

The mode of operation of theiadditional appa,- ratus ior controlling 4the-second charging source I3, as above described, is asfollows:

If the contacts 31 -of relay-38 are opened in response to lriseo battery voltage before the insulating insert 43 of thetiming disk passes under brushl and opensthecircuitbetween conductorsiil and 43, the excitationof relay'52, which 'may be called a conditioning relay, will-be inten ruptedand contacts 54 will open, -This Will interrupt the lexcitation of intermediate relay 60 and open thecontacts j4and `t5. The excitation of` intermediaterelays55 will not be interrupted until'the insulating-insert 49jpaSSYS lLinder brush 5 l ,'so'that contact 58 will remainclosed and contact 59 will be open. The exciting-circuits of relay 61 will be openat contacts 54 as well as at contacts and 59, vThe contacts 1I beingthus op'en'the excitation offcontactor 23'will loe-interrupted and the contacts V22 'will be Y open, leaving charging source l3disconnected.

"Whenthe rotation of the timerv disk opensvthe circuit' between conductors 4l :and 43- afterA relay has operatedtoopen thev contacts 31the 'excitingV circuit Vof/relay 5,51 will Ybe opened permitting contacts-58 to open and'contacts'S-'to close. Whilethe opening of circuit 4l,^43at=the timing disk will also open the exciting `circuit of relay 38, permitting the contacts-31 to "close, thus; closing the exciting circuit` ofi-relay 52 'and thereby closing contacts 54, this will require -a slightly longer time thanfthe openingof'con` tacts 58,y so that theclosing of contacts154` cannot re-establish the excitation of relayfi,-tandI therefore, the second charging source g l 3;;wil'1'remain disconnecte .mitting contacts 58 .05, 59' and se, cited, thus closing contacts l to excite contactor l23and connect to the A. C. circuit the second the operation of the timing lf, however, during the rotation of the timing ydisk the battery voltage has failed to rise to the `value required to operate relay 38, owing to the unusually heavy load conditionsabove referred Vto, thecontacts 3'! will remain closed when the circuit 4i, 43 is interrupted at the timing disk,

s 'o that, while the interruption of circuit 4|, 43 vwill open the exciting circuit of relay 55, perto open and contacts 59 to close, the opening of contacts 58 will not interrupt the exciting circuit of relay 60 via bus 2 4, conductor 55, contacts 54, conductors 63 and l62,coil 65a, contacts 6K3, conductor 66 and bus 26; kfor contacts 54 have remained closed by reason `of the sustained excitation o1 relay 52 via contacts 3l. Under these conditions, contacts being closed, relay 61 will be excharging source i3, whose output will be added to that of the irst charging source I2, thereby increasing the charging rate to the battery to .compfnsate for the increased load.

Charging source y I3 will thus remain in operation in addition to source i2 independently of disk until the battery voltage rises sufficiently to open the contacts 3l. `When this occurs, the excitation of relay 33 will be interrupted, thus opening contacts 32 and interrupting the excitation of contactor 2i, thereby disconnecting charging source i2; also the eX- citation of'relay 52 will be interrupted at contacts 3l,V opening contacts 54, thus interrupting the exciting circuits of relay 51, thereby disconnecting. charging source I3. then receive no further charge until circuit 4i, 43'is interrupted at the timing disk, which will re-conriectv charging source l2, thus 11e-establishing normal charging conditions. conditions still remain suiciently heavy', charging source i3 will again be connected upon the next interruption of circuit 4i, |13.

@Ars vpointed out above, an important feature of the charging system described is the time delay between the opening of contacts 5S resulting from the interruption of circuit 4i, 43 at the timing disk and the closing of contacts 54 to establish the exciting circuit of relay 65 after contacts 31 have been closed to excite relay 52. This time delay is assured by the fact that contacts 58 are opened instantly upon the interruption of excitation of relay 55, while the closing of contacts 54 must await the travel of the armature of relay 38 from the attracted to the released position to close contacts 31, to be then followed by the building up of excitation of relay 52 and the subsequent travel o1" its armature from the released to the attracted position. This time delay can be readily assured by the design of the relays in accordance with principles well known to those skilled in the art.

While rectiers have been shown in the above description as illustrative of suitable charging sources, it will be obvious that other well known apparatus may be substituted for supplying the charging current.

It will be obvious to those skilled in the art that modifications may be made in details of construction and arrangement without departing from the spirit of the invention.

I claim:

1. In a control circuit for a battery charging system comprising a charging source, a storage battery and a transmission circuit for transmitting charging current from the source to the bat- 'Ihe battery will If the load .tery whereof at least a portion comprises two parallel paths whereof the first is normally closed to transmit a normal charging current to the battery and the second is normally open, the combination of, means responsive to a predetermined high battery voltage for reducing the normal current through the rst path, timing means for intermittently re-establishing the normal current through said first path, and means controlled by the timing means and responsive to failure of the voltage responsive means to reduce said normal current, for closing said second normally open path, said voltage responsive means adapted in response to said predetermined high battery voltage simultaneously to reduce the current in said irst path and open the second.

2. In a charge control circuit for a storage battery, the combination with the battery and its load circuit of two sources of charge current, means for causing the transmission of charging current to the battery from said sources, voltage responsive means for controlling the operation of said first-mentioned means to reduce the transmission of charging currentl to the battery when the battery voltage reaches a predetermined value, timing means for periodically controlling the operation of said first-mentioned means to cause the transmission of full charging current from one of said sources to said battery even lthough said battery had attained said predetermined voltage and said voltage responsive means had operated, and means responsive to the operation of said timing means and the failure of said voltage responsive means to operate in the period of said timing means for causing the transmission to the battery of full charging current from both charging sources.

3. A control circuit for a battery charging system consisting of a battery connected to a source of direct current of two values, comprising means for normally subjecting the battery to the charging current of lower value, voltage responsive means for controlling the flow of charging current in response to battery voltage, timing means for periodically subjecting said battery to charging current independently of the voltage of said battery, relay means responsive to the position of said voltage responsive means at the instant of operation of said timing means for controlling the value of the charge current applied to the battery, and relay means conditioned by the failure of said voltage responsive means to operate in the period of said timing means for subjecting said battery to the charging current of higher value upon operation of said timing means.

4. A control circuit for a battery charging system consisting of a battery, its load circuit, and a source of charging current of two values comprising, means for subjecting the battery to the charging current of either value, voltage responsive means for controlling said first-mentioned means, to reduce the value of said charging currenft in response to a predetermined high battery voltage, timing means for periodically subjecting the battery to the lowerof said two values if said sive means to operate in fthe period of said timing means for subjecting the battery to the higher of said two values.

5. In a charge control circuit for a storage battery, the combination with the battery and its erated to disconnect the connected charging sources.

6. -In a charge control system for a storage battery, .the combination with i the battery .and

its load .circuit Yof two .'chargingzsources, Vcircuit connectionslfor establishing and interrupting the ltransmission of charging current from Vveach isource .to :the Lbatterygi means 4responsive to .ele-

Yvated :battery 'voltage .near the completion lof charge .for opening'such of said circuit .connec- 'tions as are established, means ,for periodically and. at predeterminedtime intervals ref-establish- -ingr-saidcircuit connections. for .one of said chargaing sources'-.yvheniopened bythe battery voltage responsive` meansand means lfor establishing the :circuit connections forv the .second charging source, r'said vmeans 'responsive to the failure Vof fthe voltage/responsive means toopen the circuit `connection =ior said one charging source as a 4'resiilt of kunusually'heavy load conditions during any 'one of saidtime intervals.

'7. lna ycharge controlsystem for a storage battery, the combination IWith thefbattery and its load circuit of twochargingsources, circuit connections 'for establishing and'interrupting the transmission of fchargingcurrent fromeach source tothe batteryfineans:responsive to battery Volltfageor opening such of sai'dzcircuit connections .as areestablished, means iorperiodically and at predetermined time intervals re-establishing said circuit :connections `for Aone Voi" Vsaid ycharging sources `When opened bythe Vbatteryvoltage re- .sponsive means, fand rneansactuatedI bythe operation ofi the isaid periodic vmeans for vestablishing Cal the circuit connections vfor Vthe second charging -source `vif the circuit connections tfor 'the vrst `charging ysourcel'lave not Abeen opened vby "the '-batltery voltage responsive means.

-i8. In al controlcircuit for a battery charging system comprising a source of charging energy, =a storagebattery and two parallel paths-includ- -ing appropriate electrical conducting circuits'for the transmission Vof saidenergy tothe battery, the lcombination of, a rst charge control relay havfing an exciting` circuit connected yacross thebattery -vvhose normally closedfcontacts are 'adapted tobe-opened-in response to a predetermined'hgh ybattery voltage to thereby eiect the interruption Aof the conducting circuit of the rst 'ofsaid paths, atiming .device adapted periodically to interrupt the'exciting circuit of said rst charge control srelay, a second charge control relay'having contacts adapted 'to close when said relay is excited Ato eiect the completion of the conducting circuit ofthe second of saidpaths, Ia -iirst and a second intermediate relay and a conditioning relay controlling respectively three pairs of contacts interposed in series in the exciting circuit of the second charge control relay, whereof the contacts controlled "by the conditioning relay and the Vsecond intermediate relay are closed and `those controlled by the first intermediaterelay are opened When said relays vare respectivelyA excited, an exciting circuit for the conditioning relay in Which the contacts of the first charge control relay are interposed, an exciting circuit for the rst intermediate relay adapted tobe opened periodicallyby the timing device simul- `taneously with its opening of'the--eXciting-circuit of the'iirst charge control relay, `anexciting'circuit for the second intermediate relay including in series-relation the contacts of the conditioning relay and contacts vclosed bythe rst intermediate relay Awhen said relay is excited, and holdingfexvcitation circuits for'the second intermediaterelay and the second charge control relay, respectively,

each of said-circuits including a-contactheld closed by'itszrespective relay when excited, and both of said two holding excitation circuitsconrtrolled in parallel by the conltacts of 'the conditioning relay.

SAMUEL K. LESSEY. 

